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Old 12-12-2017, 10:08 AM   #21
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Quote:
Originally Posted by Lou_tribal View Post
Depending on the wavelength you may try this:



or this



L


Very funny Lou!
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Old 12-12-2017, 12:49 PM   #22
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Your vhf radio transmits 25 watts. Just sayin’
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Old 12-12-2017, 01:12 PM   #23
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Your vhf radio transmits 25 watts. Just sayin’
I don't understand the point you are trying to make. Can you elaborate?
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Old 12-12-2017, 01:56 PM   #24
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The limit to non-ionizing radio energy is a function of its heating power. So, calculations are made for beamwidth, distance from subject, transmit power, transmit duty cycle, beam direction, and frequency. Did you know that around 2 meters wavelength (145 to 155MHz) is near the optimum for body absorbtion?

I had worked for a "major 2 way radio provider" when we were strapping 800MHz radios on live pigs to see what would happen.
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Old 12-12-2017, 02:24 PM   #25
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(This is related to my field of engineering)
Depends on the model, but for example a Garmin xHD shows an output of 4,000 Watts, horizontal beamwidth of 5 degrees and vertical beamwidth of 25 degrees (= + 12.5 degrees).
The vertical is wider to allow your boat to pitch up and down in higher sea states yet still maintain adequate power at the horizon to track objects in your path.
This doesn't mean it cuts off at exactly -12.5 degrees. think of the beam as a sort of elongated balloon. the beamwidth edges are typically the point where peak power has fallen off no more than 3 dB.
As others mentioned, we're talking the electromagnetic band here... you have to get above ~ 100 Teraherz to get into the ionizing band where a dosimeter would work.
Since this is non-ionizing, the only known adverse effects are thermal. You could take some measurements and figure distance from antenna as well as angle, but power dissipates rapidly in radar bands. What really drops any risk is the fact these antennas are constantly rotating, so power doesnt stay in one place.
Sorry, this is too much information; suffice to say I wouldn't climb up and do several minutes of maintenance on my mast with radar running... but otherwise they are pretty safe.
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Old 12-12-2017, 05:11 PM   #26
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On this exact subject the November 2017 issue of Power and Motoryacht had an article. The experts concluded no safety issues for the radars recreational boaters normally use. It was a good article and cited Furuno, Garmin and Simrad findings.

The last sentence in the article stated one has more risk (if any) from cooking a burrito in a microwave which relies upon a steady radio frequency wave vs pulsed that are used in radars.
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Old 12-12-2017, 05:26 PM   #27
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Quote:
Originally Posted by sunchaser View Post
On this exact subject the November 2017 issue of Power and Motoryacht had an article. The experts concluded no safety issues for the radars recreational boaters normally use. It was a good article and cited Furuno, Garmin and Simrad findings.

The last sentence in the article stated one has more risk (if any) from cooking a burrito in a microwave which relies upon a steady radio frequency wave vs pulsed that are used in radars.
https://www.powerandmotoryacht.com/e...eally-hurt-you
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Old 12-12-2017, 05:58 PM   #28
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Don't worry about our little boat radars hurting you. ....
40 years in nuclear power hasn't had any affect on me!
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Old 12-12-2017, 08:56 PM   #29
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My radar is about 15 feet overhead and need not worry.
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Old 06-10-2018, 02:30 PM   #30
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I know this post is a year old, I'm surprised no one mentioned this. Not trying to sound like a salesman for Simrad, however The Simrad/Lowrance 3G and 4G radar put out less radiation than a cell phone, and quite frankly what you get on the screen is unbelievable resolution and return (with overlay capabilities onto the chart).
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Old 06-10-2018, 05:38 PM   #31
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That’s true. But also true for conventional pulse radar at less that 1m distance. Unless you are hugging your radar dome, the Simrad is no lower emission than others. Don’t fall for their BS.
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